The heir to the throne also allegedly campaigned to alter climate change agreements without disclosing his private estate had a financial interest in such a rule change, according to BBC Panorama.

The latest accusations on Tuesday came after it was revealed that the Queen’s private estate invested in controversial retailer BrightHouse as part of £10 million paid into funds in the Cayman Islands.

The chief finance officer of the Queen’s £500m estate, Chris Adcock, told the BBC: “Our investment strategy is based on advice and recommendation from our investment consultants and appropriate asset allocation...

“The Duchy has only invested in highly regarded private equity funds following a strong recommendation from our investment consultants.”

A Clarence House spokesman said to the BBC that the Prince of Wales had “certainly never chosen to speak out on a topic simply because of a company that it may have invested in.

“In the case of climate change his views are well known, indeed he has been warning of the threat of global warming to our environment for over 30 years.

“Carbon markets are just one example that the prince has championed since the 1990s and which he continues to promote today.”